14. Make the Filling
Scoop the flesh of the squash into a food processor and blend until very smooth. It is okay if the squash is still a little warm; the cold half and half will cool it completely. Measure out 1 3/4 cups (375g) of the fresh squash purée and place it in a large bowl. Reserve any remaining purée for another use.
Whisk in the half and half, brown sugar, cinnamon, ginger, nutmeg, salt, and vanilla until very well combined. Whisk in the eggs, egg yolk, and cornstarch until completely smooth. Pour into the crust.